DE2839662C2 - Device for moving the swash plate of a swash plate compressor provided with a swash plate which can be axially displaced to adjust the flow rate - Google Patents

Description

The invention relates to a device for moving the swash plate with one for adjustment of the delivery flow of axially displaceable swash plate provided swash plate compressor, which has a housing, Cylinders arranged in the housing, pistons which can be moved back and forth in these and one mounted in the housing Has drive shaft for moving the swash plate acting on the piston.

A device of the type described above is known from CH-PS 5 10 199. This well-known The device causes an axicle displacement of the swash plate, whereby the flow rate over the changed Stroke adjustment of the piston can be controlled. The axial displacement of the swash plate takes place in this case by a special adjusting plug to which a control pressure is supplied, which is either supplied by a Pump is generated, the pressure of which can be regulated, or that from the discharge pressure of the compressor is derived. The flow rate setting is therefore independent of the suction pressure and the housing pressure.

It is also a device for moving the swash plate of a swash plate compressor Adjustment of the flow rate known (US-PS 38 61 829), which formed in the fluid-tight Compressor housing controls the prevailing pressure as a function of the suction pressure and thus the flow rate adjusts. In this case, the housing pressure is diverted into the compressor intake line via the device; the case pressure cannot be increased by connecting the case to the outlet pressure will. The swash plate has a special actuating piston, which is controlled by a constant, in a Pump generated control pressure is applied and the swash plate in the direction of the maximum flow rate adjusted. The swash plate is not mounted axially displaceably on the drive shaft, but is arranged pivotably.

In both known devices results from the arrangement of the special actuating piston and the Devices for generating the control pressure acting on the actuating piston involve considerable structural effort. The invention is based on the object of providing a device of the specified type with a simplified To create structure.

According to the invention, this object is achieved in a device of the type described at the outset in that that they the fluid-tight housing interior depending on the suction pressure applied either to the suction pressure itself or to the outlet pressure

In the invention, the flow rate is adjusted by modifying the pressure in the fluid-tight trained compressor housing, namely the housing is both with the suction pressure, as well as the discharge pressure of the compressor when the suction pressure increases and thereby a need for additional capacity is indicated, the device acts on the housing the outlet pressure, so that the flow rate is increased. A decrease in suction pressure indicates that the capacity of the compressor must be reduced. The device acts on the housing the suction pressure, so that the housing pressure is relieved and the flow rate is reduced.

By modifying the case pressure in the manner described above, the swash plate shifted between two fixed positions along the axis of the drive shaft, d. H. "swim". This moves the top dead center of the piston so that it is in the most retracted position there is a considerable amount of free space. In this position of the swash plate, the flow rate is on least. The predominant free volume is in the most advanced position of the swash plate lowest, so that the highest possible flow rate is achieved.

With the device according to the invention can thus be a proper adjustment of the flow rate of the Achieve dew-disk compressor without a particularly high structural effort is required for this. This is achieved on the one hand by the fact that there is no separate adjusting cylinder for moving the swash plate is provided, but that this is shifted via the housing pressure and, on the other hand, by the fact that the housing can be subjected to both the suction pressure and the outlet pressure. With Compressors equipped with the device according to the invention therefore have cost advantages over this the well-known compressors.

An advantageous embodiment of the subject matter of the invention is described in the dependent claim.

It should also be pointed out that a compressor equipped with the device according to the invention cannot be operated down to capacity zero. However, it can be built to be inside a range between approximately 100% and 15% of the capacity. If a capacity is below 15% is required, a clutch can be used to drive the compressor under these conditions.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawing; it shows

1 shows an axial section through a swash plate compressor;

F i g. 2 shows a cross section through the compressor of FIG. 1 according to line H-II, with part of the valve plate

has broken away;

F i g. 3 shows a section along line III-III of FIG. 1;

F i g. 4 shows a partial section through the device for moving the swash plate, which on one side of the compressor housing is arranged

First of all, reference is made to FIG. 1 referred to. A compressor is shown here which has a housing 10 This is essentially bell-shaped and has a large open end at 12. This is (with the exception of the oil distribution channels, which are described below) through a valve plate assembly 14 and a Head part 16 closed. The opposite end of the compressor (in Fig. 1 on the right) has a bore 18 and an axially extending projection 20. This creates space for a seal 22 formed The housing 10 thus encloses in a fluid-tight manner Way an interior space 11.

A drive shaft 24 extends through a sealing plate 26 which is attached to the protrusion 20. she can be with a drive device, for example a belt pulley or a direct drive (not shown), be equipped. When used in the automotive industry, the compressor is normally through a V-belt driven by an accessory drive pulley within the engine compartment. With certain Applications, however, a direct drive is desired, with or without a coupling part.

The drive shaft 24 is provided with a bearing flange 28 at one end, which a thrust bearing 30 and a radial bearing 32 is in contact. The latter is arranged in an opening in the housing 10. The other end of the The drive shaft, which is designated by 34, is mounted in a counterbore 36 which is in the cylinder block 38 is trained. The latter is held inside the housing at its left end. A radial bearing is arranged within the counterbore 36 and supports the end of the drive shaft.

A cam part 42 is driven by the drive shaft via a ball wedge. There is a number of spherical elements 55 distributed over the circumference (see FIG. 3) within complementary grooves 45 or 47, which are formed on the outer surface of the drive shaft 24 and on the inner surface of a bore 46 which extends through the cam part 42. In this way, from the drive shaft on torque is transmitted to the cam part; there is also an axial "swimming movement" of the cam part possible to and fro on the drive shaft. A sleeve 37 with radial holes ensures the correct one Distance between the balls and prevents them from emerging from the annular space between the outer diameter the Aiiifiebsweiie 24 and the inner diameter of the Move hole 46 out. The thrust bearing 41, which is arranged on the sleeve section 75 of the cam part is. touches the central portion of the cylinder block 38 when the cam member is in the outermost left position (in the view of Fig. 1) moved.

A cylindrical piston 48 is slidable in an axial bore 49 which extends partially through the Drive shaft 24 extends. A cross pin 51 is attached to the piston and runs through opposite one another Slots 53 (only one of which is shown) in drive shaft 24. It is on the cylindrical sleeve portion 55 of the cam part inserted. A spring 57 lies between the piston 48 and the blind end 59 of the Hole 4 ″) and in this way presses the cam part to the left (in the view of FIG. 1).

A swash plate 50 is mounted on the cam part 42 mounted This is supported by three sets of bearings. This is a front thrust bearing 52, a rear thrust bearing 54 and a radial bearing 56. A balance ring 58 attached to the front portion of the cam member 52 is attached is attached there with machine screws 43 (see FIG. F i g. 3). The front thrust bearing 52 lies between the compensation ring 58 and the swash plate 50. The swash plate 50 is against rotation secured by a ball part 60, which between two Cushion 62 (see Fig. 3) is arranged in one of the parts 63 and 64 in the vicinity of the lower housing portion formed path are movable. This arrangement gives the swash plate both degrees of freedom around its vertical as well as its horizontal axis; however, the swash plate is prevented from moving rotated relative to the housing - on the other hand, allow the bearings 52, 54 and 56, which the swash plate wear on the cam part that the cam part rotates freely with respect to the swash plate. One Rotation of the cam part thus leads to a wobbling movement of the wobble plate. The swash plate pivots about the axis of the pin 61, which extends through the ball part 60 and fixes it; aside from that it oscillates backwards and forwards in the path formed by the parts 63 and 64.

The swash plate 50 drives the pistons 70, which can be moved to and fro in cylinders 72. the Cylinders are formed in the cylinder block 38. Thereby gas or steam, which or which in the gas work rooms 71 is admitted, compressed. Connecting rods 76 each have a first ball end 77 formed, which is arranged in a complementary base 78 in the swash plate, and with a second ball end 80, which is supported by a complementary base 82 in the base portion of the piston 70 is surrounded.

As best shown in FIG. 2 can be seen, the valve plate 14 is provided with several discharge openings 90, one for each cylinder. These are covered by flap-like exhaust valves 92 (only a typical Valve is shown). A series of suction ports 94 arranged in groups near each cylinder are covered by suction valves 96. A section of the valve plate is broken away at one of the suction valves 96 to show c'ie between the bottom the valve plate 14 and the upper surface of the cylinder block 38 are fixed. The head part 16 is with a rib 100 which forms a continuous wall through the space that is formed by the peripheral wall 17 of the head part 16 is included. This moves the head into a first, inner chamber 102, which in Fluid communication with all suction openings 94 is, and a second, outer chamber 104 is divided, which are in fluid communication with the outlet

5 '. openings 90 stands. In the portion of FIG. 2 broken away to show the suction valve, the rib 100 would follow the dashed line labeled 101.
Suction gas is introduced into the chamber 102 via a duct

bo 106 let in from a connector 108, which is thus in fluid connection with all suction openings 94 stands. On the other hand, due to the outlet openings 90 which are in communication with the chamber 104, the discharge gas through a passage 110 to one

e> 5 connection piece to be diverted.

An oil breaker 31 rotates with the shaft 24 in sealing contact with the face of the valve plate 14. The inclined hole 33 coincides intermittently

the hole 35, whereby oil can return from the outlet cavity 104 into the housing interior 11

The setting of the delivery flow of the compressor takes place via a device 122 for axial displacement the swashplate. This causes either fluid under outlet pressure into the interior of the housing introduced or withdrawn fluid therefrom into the suction zone. The device is in the F i g. 2 and 4 and includes a chamber 114, the is formed along one side of the compressor housing 10. This takes a gas-filled, sealed one Bellows 120, which is set to the suction pressure. A valve arrangement 122 is assigned to the bellows 120, which a slide 124 comprises. This has spaced-apart webs 125a and 1256 and one in between Groove 126. The slide can be moved within a blind bore 128, which is at a distance arranged grooves 130,132 is provided. These grooves are located in the housing via channels 134, 136 (cf. Fig. 2) in connection with the outlet or suction pressure. The slider contacts the bellows 120 at one end and at the other end a spring 138. This spring is under compression and pushes the slide (in the View from FIG. 4) to the left. A channel 140 and a transversely drilled hole 141 connect the annulus therebetween the webs 125a and 125b with the chamber 142. In this the spring 138 is at the right end of the slide housed. The chamber 142 is connected to the crankcase 11 via the channel 144.

As mentioned above, the chamber 114 communicates in which the bellows 120 is arranged, with the suction chamber 102. It is therefore always at the suction pressure surround. Discharge pressure is available at groove 130 while suction pressure is available at groove 132. If the If the suction pressure increases and indicates a need for additional capacity, the increased pressure acts on the Bellows and contracts its length. The valve slide 124 moves under the force of the spring 138 left, so that gas under discharge pressure from the groove 130 into the groove 126 and the transversely drilled hole 141, from there Flows into the housing interior 11 via the channel 140, the chamber 142 and the channel 144. Due to the increase in pressure inside the housing, the entire swash plate is shifted to the left on the drive shaft (supported by the spring 57). This is due to the additional forces acting on the back of the piston works. An equilibrium point is reached when the suction pressure is OK; at this point the swash plate stabilizes.

A decrease in suction pressure indicates that the capacity of the compressor must be reduced. The lower suction pressure causes the bellows 12G to expand, moving the spool 124 to the right. This opens up a gas path from the housing interior 11 into the suction chamber 102 via the following route: Channel 144; Chamber 142; Channel 140; Groove 126; Groove 132; Channel 136. If the pressure inside the housing drops, the force on the back of the pistons 70 is relieved; the swashplate "floats" to the right (against the Force of the spring 57), whereby the free volume is increased and the capacity is reduced, until the forces are balanced at the equilibrium point.

For this purpose 2 sheets of drawings
65

Claims (2)

Patent claims: 1. Device for moving the swash plate with one for adjusting the flow rate axially slidable swash plate provided swash plate compressor, which has a housing with a has fluid-tight housing interior, arranged in the housing cylinder, in this reciprocating piston and a drive shaft mounted in the housing for moving the has swash plate acting on the piston, characterized in that it encompasses the interior of the housing depending on the suction pressure either with the suction pressure itself or with the Outlet pressure applied 2. Device according to claim 1, characterized in that it has a contracted and expandable BaJg (120) which is acted upon by the suction pressure and controls a slide (124) which, depending on the contraction or expansion of the bellows (120), either one with the outlet pressure or a channel (134, 136) connected to the suction pressure with the housing interior.